Bug 1221673 – CVE-2015-3644 stunnel: authentication bypass with the "redirect" option

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Bug 1221673 - (CVE-2015-3644) CVE-2015-3644 stunnel: authentication bypass with the "redirect" option

Summary:	CVE-2015-3644 stunnel: authentication bypass with the "redirect" option

Status:	CLOSED NOTABUG

Aliases:	CVE-2015-3644

Product:	Security Response
Classification:	Other
Component:	vulnerability (Show other bugs)
Sub Component:
Version:	unspecified
Hardware:	All Linux

Priority	high Severity high
Target Milestone:	---
Target Release:	---
Assigned To:	Red Hat Product Security
QA Contact:
Docs Contact:

URL:
Whiteboard:	impact=important,public=20150514,repo...
Keywords:	Security

Depends On:	1221674
Blocks:
	Show dependency tree / graph

Reported:	2015-05-14 10:15 EDT by Martin Prpič
Modified:	2015-05-15 01:58 EDT (History)
CC List:	2 users (show)

See Also:
Fixed In Version:	stunnel 5.14
Doc Type:	Bug Fix
Doc Text:
Story Points:	---
Clone Of:
Environment:
Last Closed:	2015-05-14 10:17:00 EDT
Type:	---
Regression:	---
Mount Type:	---
Documentation:	---
CRM:
Verified Versions:
Category:	---
oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---

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Description Martin Prpič 2015-05-14 10:15:50 EDT

The following flaw was found in stunnel:

Normally, clients are connected to the host(s) specified with the "connect" option on authentication success, and rejected on authentication failure (untrusted client certificate). When the "redirect" option is specified, such connections are supposed to be forwarded to the host(s) specified with "redirect" rather then rejected.

In Stunnel versions 5.00 to 5.13, only the initial connection is redirected to the host(s) specified with "redirect". The subsequent connections established with reused SSL/TLS sessions are always forwarded to the host(s) specified with "connect" as if they were successfully authenticated.

The vulnerability is exploitable under the following conditions:

- Stunnel versions 5.00 to 5.13 inclusive.
- Server mode mode is enabled with "client = no" (which is the default).
- Certificate-based authentication is enabled with "verify = 2" or higher.
- The "redirect" option is used.

Upstream advisory:

https://www.stunnel.org/CVE-2015-3644.html

Comment 1 Martin Prpič 2015-05-14 10:16:11 EDT

Created stunnel tracking bugs for this issue:

Affects: fedora-all [bug 1221674]

Comment 2 Martin Prpič 2015-05-14 10:17:00 EDT

Statement:

Not vulnerable. This issue did not affect the versions of stunnel as shipped with Red Hat Enterprise Linux 5, 6, and 7.

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